(Previous in the series: Introduction, Overview, On Species, Peculiarities. Full text of Cartwright’s paper can be found here in three parts on pages 64, 209, 331 and with a response to critics on page 504.)
We last left Dr. Cartwright discussing how the bones of black people different from those of white people, contributing to his position that the two races constitute separate species. Having cited the greater hardness of the bones, which heavy labor would explain regardless of one’s race, and the supposed greater thickness of the skull for which Cartwright cited only an ancient authority of questionable accuracy working in an unrelated field, he still had more to say.
Going beyond composition of the skeleton and general posture, Cartwright makes more direct, empirical claims:
the thigh-bones [are] larger, and flattened from before backwards; the bones more bent; the legs curved outwards, or bowed; the feet flat; the gastrocnemii muscles so long, as to make the ankle appear as if planted in the middle of the foot; the gait, hopper-hipped […] not unlike that of a person carrying a burden
A lifetime of heavy labor would go a long way to explaining the flat feet. They can also come from illness and, while I cannot say this with an expert’s confidence, I imagine slaves did not as a whole receive the same quality of nutrition that white people, especially their white owners, got. Malnutrition weakens the body’s ability to fight off illness and hard labor invites injury, both known causes of flat feet.
For the rest, modern science does know a condition where the legs bow out and bones bend. To those symptoms we may add asymmetrical or odd-shaped skulls, bumps on the ribs, a pushed-forward breastbone, pelvic deformities, and abnormal curvature of the spine. Cartwright has found real peculiarities, but he blames on race the products of rickets. How does one acquire a case of rickets? Malnutrition, certain liver, kidney, and intestine diseases, and occasionally through bad genes. Just as with flat feet, we must point a finger at the realities of slavery.
Cartwright could not know that as no one knew the causes of rickets until the 1920s. But fairness does not obligate us to give him a pass on recognizing the disease when he saw it. Having such obvious symptoms made rickets a feature in medical literature dating back to antiquity. It received substantial attention beginning in the seventeenth century, two hundred years before Cartwright. Nor we can excuse Cartwright on the grounds that linguistic barriers kept him from the literature as rickets had the attention of the English medical community.
The Louisiana physician had perfectly good eyes. He saw the symptoms. He had a perfectly good education for his time. He should have recognized those symptoms. Medical science knew of rickets. He cannot claim ignorance. With these facts at hand, I cannot explain how he comes to see its fairly obvious symptoms as instead diagnostic traits of a separate species unless he had already concluded that black people amounted to a species apart on grounds unrelated to skeletal anatomy and went looking for evidence after the fact.
Cartwright would of course respond that he did not, in fact, rest his case on the skeletons. He had still more anatomical distinctions to cite.